High-Dose Prophylactic Anticoagulation for COVID-19 Pneumonia: A Review of Benefits and Risks.

The COVID-19 pandemic has had a devastating impact on a global scale, causing significant morbidity and mortality. The virus affects multiple organ systems, including the respiratory, cardiovascular, and coagulation systems, leading to severe pneumonia in some patients. Moreover, COVID-19 patients with severe pneumonia have a high incidence of thrombotic events, which can result in significant morbidity and mortality. Given the potential benefits of anticoagulation therapy in COVID-19 patients with thrombotic complications, recent studies have proposed high-dose prophylactic anticoagulation (HD-PA) therapy as a potential treatment option. In fact, some studies have suggested that HD-PA therapy may be more effective in reducing thrombotic events and mortality rates than other treatment options. This review aims to provide a comprehensive overview of the benefits and risks of HD-PA therapy for COVID-19 pneumonia patients. By synthesizing and analyzing the latest available research, we highlight patient selection criteria and discuss the optimal dosage, duration, and timing of therapy. Additionally, we review the potential risks associated with HD-PA therapy and provide recommendations for clinical practice. Ultimately, this review provides valuable insights into the use of HD-PA therapy in COVID-19 pneumonia patients and paves the way for further research in this critical area. By exploring the benefits and risks of this treatment option, we hope to provide healthcare professionals with the information they need to make informed decisions about the best course of treatment for their patients.

Superior Mesenteric Artery Thrombosis and Intestinal Ischemia as a Consequence of COVID-19 Infection.

COVID-19-associated arterial and venous thrombotic events are multifactorial in origin, resulting in significant morbidity and mortality. Intestinal ischemia due to thrombus is a rare manifestation of COVID infection. Here, we report the case of a patient who presented with fever, malaise, and diarrhea, and was found to be COVID-19 positive; his clinical course was further complicated by devastating thrombosis of the superior mesentery artery (SMA) associated with COVID-19 infection.

Cerebral venous sinus thrombosis (CVST), an unusual presentation of COVID-19: A case report from Bangladesh

Newly recognized pandemic infectious disease COVID-19 (Corona-virus disease) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This viral infection causes hypercoagulability and inflammation leading to increased incidence of both arterial and venous thrombotic events (VTEs). Therefore, patients infected with this novel virus seem to be at higher risk of thrombotic events (TEs) resulting in thromboembolic diseases, especially stroke and pulmonary embolism, or even cerebral venous sinus thrombosis (CVST). We report a case of 42-year-old female, presented with features of venous thrombotic events (extensive dural venous sinus thrombosis) and was subsequently found to have COVID-19 positive by reverse transcriptase-polymerase chain reaction (RT-PCR) test. The case report indicates CVST might be an unusual manifestation of COVID-19. Cerebral venous sinus thrombosis even presents as an initial symptom of COVID-19 without significant respiratory symptoms. Early diagnosis and treatment with thrombolytic agent in case of SARS-CoV-2 infection result in reduced morbidity and mortality. We recommend further studies to establish SARS-CoV-2 virus (the COVID-19 disease) as a known risk factor for CVST. © 2020 The author (s).

Thromboembolic Diseases Among Intensive Care Unit Patients in Al-Qassim Region, Saudi Arabia.

Background Venous and arterial thrombotic conditions are the two types of thromboembolic events. Main venous thromboembolism (VTE) includes deep vein thrombosis (DVT) and pulmonary embolism (PE), while arterial thromboses include ischemic stroke and ischemic heart disease (IHD). Aim This study aimed to assess the prevalence of thromboembolic events among intensive care unit (ICU) patients in Al-Qassim region, Saudi Arabia. Patients and methods This is a retrospective chart review of ICU patients diagnosed with thromboembolic disease who were seen at the intensive care unit of King Fahad Specialist Hospital between July 2020 and June 2022. Data were obtained from hospital medical files and gathered into an Excel sheet (Microsoft Corp., Redmond, WA, USA). All data analyses were carried out using Statistical Package for the Social Sciences (SPSS) version 26 (IBM SPSS Statistics, Armonk, NY, USA). Results Of the 38 patients included, 52.6% were males (mean age: 60.7; standard deviation (SD): 23.9). The most common risk factors for thromboembolic events were immobilization (23.7%) and major surgeries (18.4%). The incidence of DVT was 42.1%, while PE was 39.5%. Seven patients were detected with combined incidence (DVT and PE). Mortality rates accounted for 39.5%. It is interesting to note that the prevalence of patients who use heparin treatment was statistically significantly higher among DVT patients (p=0.043). Conclusion The incidence of deep vein thrombosis was 42.1%, while pulmonary embolism occurred in 39.5%. However, 18.4% of the ICU patients had an occurrence of both DVT and PE. Furthermore, immobilization was identified as the most common risk factor for thromboembolic events, followed by major surgeries. More research is necessary to determine the incidence and prevalence of thromboembolic disease and its manifestations.

The Challenge of High Coronary Thrombotic Events in Patients with ST-Segment Elevation Myocardial Infarction and COVID-19.

The aim of this observational study was to describe the characteristics and outcomes of coronavirus disease 2019 (COVID-19)-positive patients with ST-segment elevation myocardial infarction (STEMI), with a special focus on factors associated with a high risk of coronary thrombosis and in-hospital mortality. Comparing the two groups of patients with STEMI separated according to the presence of SARS-CoV-2 infections, it was observed that COVID-19 patients were more likely to present with dyspnea (82.43% vs. 61.41%, p = 0.048) and cardiogenic shock (10.52% vs. 5.40%, p = 0.012). A longer total ischemia time was observed in COVID-19 patients, and they were twice as likely to undergo coronary angiography more than 12 hours after the onset of symptoms (19.29% vs. 10.13%, p = 0.024). In 10 of 57 COVID-19-positive patients, a primary PCI was not necessary, and only thromboaspiration was performed (17.54% vs. 2.70%, p < 0.001). Platelet level was inversely correlated (r = -0.512, p = 0.025) with a higher risk of coronary thrombosis without an atherosclerotic lesion. Using a cut-off value of 740 ng/ml, D-dimers predicted a higher risk of coronary thrombosis, with a sensitivity of 80% and a specificity of 66% (ROC area under the curve: 0.826, 95% CI: 0.716-0.935, p = 0.001). These are novel findings that raise the question of whether more aggressive antithrombotic therapy is necessary for selected COVID-19 and STEMI patients.

Increased Susceptibility for Thromboembolic Events versus High Bleeding Risk Associated with COVID-19.

The infection with the SARS-CoV-2 virus is associated with numerous systemic involvements. Besides the severe respiratory injuries and cardiovascular complications, it became obvious early on that this disease carries an increased risk of thromboembolic events, but a higher propensity for bleedings as well. We researched the medical literature over significant PubMed published articles debating on the prevalence, category of patients, the moment of occurrence, and evolution of venous thromboembolism (VTE), but also of venous and arterial "in situ" thrombosis (AT), and hemorrhagic events as well. Most researchers agree on an increased prevalence of thromboembolic events, ranging between 25 and 31% for VTE, depending on the analyzed population. For AT and hemorrhagic complications lower rates were reported, namely, about 2-3%, respectively, between 4.8 and 8%, occurring mostly in older patients, suffering from moderate/severe forms of COVID-19, with associated comorbidities. It is important to mention that patients suffering from hemorrhages frequently received thromboprophylaxis with anticoagulant drugs. As a consequence of thromboembolic and hemorrhagic complications which are both important negative prognostic factors, the evolution of patients infected with the SARS-CoV-2 virus is aggravated, determining an augmented morbidity and mortality of this population.

Late Onset Occurrence of Concomitant Myocardial Infarction and Ischemic Stroke in Hospitalized COVID-19 Patient: A Case Report.

We described the case of a 68-year-old COVID-19 patient with hypertension and dyslipidemia who discontinued the cardiovascular medications during hospitalization and experienced a late onset occurrence of concomitant ST-elevation myocardial infarction and ischemic stroke at resolution of SARS-CoV-2 pneumonia.

Risk of thrombotic events and other complications in anticoagulant users infected with SARS-CoV-2: an observational cohort study in primary health care in SIDIAP (Catalonia, Spain).

BACKGROUND: The risk of thromboembolic events and COVID-19 complications in anticoagulated patients once hospitalized has been widely analyzed. We aim to assess these outcomes in primary health care (PHC) patients chronically treated with oral anticoagulants (OAC) in comparison with non-treated. METHODS: Cohort study including adults with COVID-19 diagnosis in the PHC records in Catalonia, Spain; from March to June 2020. Patients were matched between exposed and non-exposed to OAC based on age and gender in a 1:2 design. Data source is the Information System for Research in Primary Care (SIDIAP). RESULTS: We included 311,542 individuals with COVID-19. After propensity score matching, we obtained a cohort of 20,360 people, 10,180 exposed and 10,180 non-exposed to OAC. Their mean age was 79.9 and 52.1% were women. Patients exposed to OAC had a higher frequency of comorbidities than non-exposed. Anticoagulated patients had a higher risk of hospital admission (IRR 1.16, 95% CI 1.03-1.29), and of stroke and pulmonary embolism than non-anticoagulated (IRR 1,80, 95% CI 1.06-3.06). The risk of pneumonia was not different between groups (IRR 1.04, 95% CI 0.84-1.30). We found a lower risk of death in patients exposed to OAC (IRR 0.60, 95% CI 0.55-0.65). CONCLUSIONS: OAC users in our study had more comorbidities and were older than non-users, well known risks for hospitalization being confirmed with our results. We also found in our study that OAC exposure was not associated to an increased risk in the mortality rate, and it was associated with higher risks of hospital admission and thromboembolic events, although we cannot assess the effect of the interventions applied during hospital admission on the outcomes studied, as our database is a PHC database. TRIAL REGISTRATION: EUPAS register: EUPAS37205 .

Cerebral venous sinus thrombosis in COVID 19 patients: Report of 2 cases.

Background: Initially, novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) was considered primarily a respiratory pathogen. However, with time it has behaved as a virus with the potential to cause multi-system involvement, including neurological manifestations which varies from acute to subacute onset of headache, seizures, a decrease of consciousness, and paralysis. Case description: Two cases of cerebral sinus venous thrombosis in COVID-19 patients were reported, following respiratory disorders, which was triggered by the SARS-CoV-2 infection. The first patient, presented with a decrease in level of consciousness and hemiparesis, was 23 years old female having no history of previous medical co-morbidities. The latter case, 21 years old woman showed less severe presentations of COVID-19 associated with headache, vomiting and papilledema. These two cases marvellously improved with no neurological deficit with aggressive course of anticoagulation. Conclusion: CVST should be suspected in COVID-19 patients presenting with headache, paralysis, aphasia or seizures. The high mortality rate of CVST in COVID-19 infection warrants a high index of suspicion from physicians, and early treatment with anticoagulation should be initiated.

Thromboembolic Events in a Socio-Economically Disadvantaged Population with COVID-19 Admitted to a Medicalized Hotel in Madrid.

Background: The social determinants of health (SDOH) of patients with COVID-19-related thrombosis have been scarcely explored. Our objective was to investigate the cases of thrombosis in a group of socially disadvantaged populations with COVID-19. Methods: We investigated the thrombotic events that occurred in a cohort of migrant and Spanish patients with COVID-19 that were admitted to a medicalized hotel in Madrid. Demographic data, past medical history, and socio-economic backgrounds, such as monthly household income, level of education, and living conditions, were explored to determine the factors related to thrombosis. Results: A cohort of 383 subjects (mean age 55.4 ± 14.6 years old, 69% male), of which 58% were migrants, was studied. Fourteen (3.6%) cases of thrombosis were reported. Thrombosis was more frequent in Spanish than in migrant individuals (OR 5.3, 95%CI 1.4-19.5, p = 0.005). Neither a low monthly household income nor a low education level showed a statistical association with thrombosis (p ≥ 0.05). History of venous thromboembolism (OR 8.1, 95%CI 2.2-28.6) and being a current smoker (OR 4.7, 95%CI 1.3-16.0) were factors associated with thrombosis. Conclusions: The SDOH studied were not associated with thrombosis; however, further investigation must be performed to investigate the socio-economic conditions of subjects with COVID-19 with adverse outcomes such as thrombotic events.

Full Characterization of Thrombotic Events in All Hospitalized COVID-19 Patients in a Spanish Tertiary Hospital during the First 18 Months of the Pandemic.

The presence of a procoagulant state, COVID-19-related coagulopathy, and an increased rate of thrombotic events (TEs) is widely known about. However, descriptive studies are scarce. Here, we conducted a large retrospective study including 2894 hospitalized COVID-19 patients followed up during the first 18 months of the pandemic to completely characterize any TE. Major TEs showed a 3.45% incidence rate. TEs were associated with increased intubation/90-day mortality risk [OR = 1.71, 95% CI (1.12-2.61), p < 0.013]. Venous thrombotic events (VTEs) were more frequent than arterial thrombotic events (ATEs) (72% vs. 28%), associated with enhanced levels of D-dimer (cross-linked fibrin derivatives formed during thrombolysis), which were related to mortality but more useful for early detection of thrombosis. In this regard, D-dimer plasma levels above 2014 µg/mL at hospital admission identify TEs with 91% accuracy (AUC = 0.91, p < 0.001), rising to almost 95% (AUC = 0.94, p < 0.001) with a cut-off value of 2666 µg/mL in VTEs. Moreover, 41% of TEs occurred in patients receiving LMWH thromboprophylactic treatments in hospital or domiciliary therapies. SARS-CoV-2 infection along with a sedentary lifestyle derived from the confinement in 2020 could be more determinant than a procoagulant state in patients with risk factors for TEs. Furthermore, the normal results obtained from the thrombophilia study after the acute process are linked to this independent procoagulant state and to SARS-CoV-2-derived coagulopathy.

COVID-19-related thrombotic complications experience before and during delta wave.

OBJECTIVE: Hypercoagulability and thrombotic complications seen in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as well as the associated pathophysiology, have been reported extensively. However, there is limited information regarding the factors related to this phenomenon and its association with the Coronavirus disease 2019 (COVID-19) Delta variant. METHODS: A retrospective review including patients admitted to a tertiary center with a COVID-19 positive test and at least one acute thrombotic event confirmed by imaging between June 2020 and August 2021 was performed. We compared the rates of thrombotic events in patients with COVID-19 before and during the Delta peak. We also analyzed the association of the thrombotic complications with demographic characteristics, comorbidities, anticoagulation strategies, and prothrombotic markers while describing other complications secondary to COVID-19 infection. RESULTS: Of 964 patients admitted with COVID-19 diagnosis, 26.5% (n = 256) had a thrombotic event evidenced by ultrasound or computed tomography scan. Venous thromboembolism was found in 60% (n = 153), arterial thrombosis in 23% (n = 60), and both venous and arterial thromboses in 17% (n = 17) of the study cohort. Of all patients, 94% were not vaccinated. Delta variant wave (DW) patients had thrombotic episodes in 34.7% (n = 50/144) of cases compared with 25% (n = 206/820) of non-Delta wave (NDW) patients, posing an estimated risk 1.36 times higher in patients infected with COVID-19 during the DW than NDW. Overall, DW subjects were significantly younger (P < .001) with lower body mass index (P = .021) compared with NDW patients. Statistical analyses showed African American patients were more likely to have arterial thrombosis compared with the other groups when testing positive for COVID-19 (odds ratio [OR], 1.78; 95% confidence interval [CI], 1.04-3.05; P = .035, whereas immunosuppressed patients had less risk of arterial thrombosis (OR, 0.38; 95% CI, 0.15-0.96; P = .042). Female gender (OR, 2.15; 95% CI, 1.20-3.85; P = .009) and patients with active malignancy (OR, 5.99; 95% CI, 2.14-16.78; P = .001) had an increased risk of having multiple thrombotic events at different locations secondary to COVID-19. CONCLUSIONS: COVID-19 infection is associated with elevated rates of thrombotic complications and an especially higher risk in patients infected during the Delta variant peak. We highlight the importance of vaccination and the development of new anticoagulation strategies for patients with COVID-19 with additional hypercoagulable risk factors to prevent thrombotic complications caused by this disease.

Arterial Thrombosis in an Unusual Site (Ulnar Artery) after COVID-19 Vaccination-A Case Report.

Spontaneous events have been reported after COVID-19 vaccination. In this case, we report a thrombotic event in an unusual site (ulnar artery) after COVID-19 vaccination. The patient (69 year-old-male) had no changes after a laboratory investigation regarding thrombophilic pattern, but nevertheless had atherothrombotic predisposing conditions. Arterial thrombotic events have more frequently been reported after mRNA vaccines than after adenovirus vaccines. This is the first case reported of thrombosis of the ulnar artery occurring in the same side of the body where the vaccination took place. However, it must be noted that COVID-19 vaccines cumulatively offer a net positive effect, despite rare adverse effects.

The importance of anticoagulation in COVID-19-related acute kidney injury requiring continuous renal replacement therapy

Introduction/Objective In Serbia, the coronavirus disease 2019 (COVID-19) pandemic began in early March 2020. The aim of this study is to summarize clinical experience in the treatment of COVID-19-associated acute kidney injury by methods of continuous renal replacement therapy (CRRT) with the focus on the amount of the administered dose of unfractionated heparin. Methods The study covers 12 patients treated with CRRT at the Clinic for Infectious Diseases at the Clinical Center of Vojvodina from March 6 to May 20, 2020. Antithrombotic prophylaxis, risk of venous thromboembolism (VTE), applied therapy, biochemical parameters before and after CRRT, anticoagulation and other CRRT parameters were analyzed. Results The mean age of the patients was 61.54 +/- 10.37 years and seven (58.3%) were men. All the patients received standard thromboprophylaxis. Nine (75%) patients had Padua Prediction Score for Risk of VTE >= 4, but none developed a thrombotic event. Seven critically ill patients with multi-organic dysfunction developed acute kidney injury dependent on CRRT. The mean CRRT dose was 36.6 ml/kg/h, the mean bolus dose of unfractionated heparin was 3250 +/- 1138.18 IU, and the continuous dose was 1112.5 +/- 334.48 IU/kg/h. Discontinuation of CRRT due to the clotting circuit was necessary in only one patient. The values of leukocytes, AST, ALT, GGT, aPTT, PT were significantly higher after CRRT compared to urea, creatinine, potassium, chlorine and magnesium, whose values were significantly lower. Conclusion In our COVID-19 patients who had high inflammatory parameters and D-dimer and an estimated risk of developing deep vein thrombosis, the implementation pre-dilution continuous venovenous hemodiafiltration with antithrombotic membrane and 1/3 to 1/2 higher unfractionated heparin doses than the recommended one, the filter life lasted with no complications.

Thrombotic events following Covid-19 vaccines compared to Influenza vaccines.

IMPORTANCE: The actual risk of thrombotic events after Covid-19 vaccination is unknown. OBJECTIVE: To evaluate the risk of thrombotic events after Covid-19 vaccination. DESIGN: Retrospective cohort study which included consecutive adult patients vaccinated with the first dose of Covid-19 vaccine between January 1 and May 30, 2021, and a historic control group, defined as consecutive patients vaccinated with influenza vaccine between March 1 and July 30, 2019. SETTING: Hospital Italiano de Buenos Aires, a tertiary hospital in Argentina. PARTICIPANTS: Non-Hospitalized Adults vaccinated with the first dose of a Covid-19 vaccine. EXPOSURE: Vaccination with Covid-19 vaccines available during the study period: Gam-COVID-Vac (Sputnik), ChAdOx1 nCoV-19 (AstraZeneca/Oxford or Covishield), BBIBP-CorV (Beijing Institute of Biological Products) (Sinopharm). Active comparator group exposure was Influenza vaccine. MAIN OUTCOME: Primary endpoint was cumulative incidence of any symptomatic thrombotic event at 30 days, defined as the occurrence of at least one of the following: symptomatic acute deep venous thrombosis (DVT); symptomatic acute pulmonary embolism (PE); acute ischemic stroke (AIS); acute coronary syndrome (ACS) or arterial thrombosis. RESULTS: From a total of 29,985 adult patients who received at least a first dose of Covid-19 vaccine during study period and 24,777 who received Influenza vaccine in 2019, we excluded those who were vaccinated during hospitalization. We finally included 29,918 and 24,753 patients respectively. Median age was 73 years old (IQR 75-81) and 67% were females in both groups. Thirty six subjects in the Covid-19 vaccination group (36/29,918) and 15 patients in the Influenza vaccination group (15/24,753) presented at least one thrombotic event. The cumulative incidence of any thrombotic event at 30 days was 12 per 10,000 (95%CI 9-17) for Covid-19 group and 6 per 10,000 (95%CI 4-10) for Influenza group (p-value=0.022). CONCLUSIONS AND RELEVANCE: This study shows a significant increase in thrombotic events in subjects vaccinated with Covid-19 vaccines in comparison to a control group. The clinical implication of these findings should be interpreted with caution, in light of the high effectiveness of vaccination and the inherent risk of thrombosis from Covid-19 infection itself.

Unusual pattern of thrombotic events in young adult non-critically ill patients with COVID-19 may result from an undiagnosed inherited and acquired form of thrombophilia.

In 145 previously healthy non-critically ill young adults, coronavirus disease 2019 (COVID-19)-related symptoms, risk factors for thrombosis, coagulation and inflammatory parameters were compared, with 29 patients reporting unusual thrombotic events (UTEs) and 116 not having thrombotic events. The inflammatory indices, coagulation and prothrombotic platelet phenotype (PTPP) were significantly higher in patients with UTEs versus those without. Patients with UTEs were categorised according to detection of thrombophilic genes (TGs), coagulation and inflammatory markers to the non-TG and TG subcohort. A total of 38 UTEs were identified, which included splanchnic vein thrombosis (SVT; 11), stroke (six), cerebral vein thrombosis (five), thrombotic microangiopathy (four), limb ischaemia and inferior vena cava thrombosis (three each), ST-segment elevation myocardial infarction (two), superior vena cava thrombosis (two), upper limb deep venous thrombosis and retinal vein thrombosis, one each. We found a 55% prevalence of TGs mainly heterozygous coagulation factor II, thrombin (FII)-G20210A, Janus kinase 2 (JAK2)-V617F, protein-S, and antithrombin III deficiency with a high (76·9%) prevalence of venous UTEs, multiple vessels thrombosis, and recurrence rate among the TG versus non-TG subcohort. The presence of JAK2-V617F, and FII-G20210A mutations was linked with SVT. Thrombosis in the non-TG subcohort was associated with more haemorrhagic problems, thrombosis progression and a significantly higher level of inflammatory markers, PTPP, mean platelet volume, von Willebrand factor, and factor VIII, which remained high for up to 6 months, as well as elevated D-dimer. Acquired and inherited thrombophilia with endotheliopathy appeared to be a relevant mechanism to explain the occurrence of UTEs that are not correlated to COVID-19 severity.

Comparison of clinical features and outcomes in COVID-19 and influenza pneumonia patients requiring intensive care unit admission.

BACKGROUND: Little is known in distinguishing clinical features and outcomes between coronavirus disease-19 (COVID-19) and influenza (FLU). MATERIALS/METHODS: Retrospective, single-centre study including patients with COVID-19 or FLU pneumonia admitted to the Intensive care Unit (ICU) of Policlinico Umberto I (Rome). Aims were: (1) to assess clinical features and differences of patients with COVID-19 and FLU, (2) to identify clinical and/or laboratory factors associated with FLU or COVID-19 and (3) to evaluate 30-day mortality, bacterial superinfections, thrombotic events and invasive pulmonary aspergillosis (IPA) in patients with FLU versus COVID-19. RESULTS: Overall, 74 patients were included (19, 25.7%, FLU and 55, 74.3%, COVID-19), median age 67 years (58-76). COVID-19 patients were more male (p = 0.013), with a lower percentage of COPD (Chronic Obstructive Pulmonary Disease) and chronic kidney disease (CKD) (p = 0.001 and p = 0.037, respectively) than FLU. SOFA score was higher (p = 0.020) and lymphocytes were significantly lower in FLU than in COVID-19 [395.5 vs 770.0 cells/mmc, p = 0.005]. At multivariable analysis, male sex (OR 6.1, p < 0.002), age > 65 years (OR 2.4, p = 0.024) and lymphocyte count > 725 cells/mmc at ICU admission (OR 5.1, p = 0.024) were significantly associated with COVID-19, whereas CKD and COPD were associated with FLU (OR 0.1 and OR 0.16, p = 0.020 and p < 0.001, respectively). No differences in mortality, bacterial superinfections and thrombotic events were observed, whereas IPA was mostly associated with FLU (31.5% vs 3.6%, p = 0.0029). CONCLUSIONS: In critically ill patients, male sex, age > 65 years and lymphocytes > 725 cells/mmc are related to COVID-19. FLU is associated with a significantly higher risk of IPA than COVID-19.

Reduced macular vessel density in COVID-19 patients with and without associated thrombotic events using optical coherence tomography angiography.

PURPOSE: Thrombotic events (TE) represent one of the major complications of SARS-CoV-2 infection. The objective is to evaluate vessel density (VD) and perfusion density (PD) by optical coherence tomography angiography (OCTA) in COVID-19 patients, and compare the findings with healthy controls. The secondary objective is to evaluate if there are differences in OCTA parameters between COVID-19 patients with and without associated TE. METHODS: Cross-sectional case-control study that included patients with laboratory-confirmed diagnosis of COVID-19 with and without TE related to the infection and age-matched healthy controls. Ophthalmological examination and OCTA were performed 12 weeks after diagnosis. Demographic data and medical history were collected. Macular OCTA parameters in the superficial retinal plexus were analyzed according to ETDRS sectors. RESULTS: Ninety patients were included, 19 (20%) COVID-19 patients with associated TE, 47 (49.5%) COVID-19 patients without TE, and 29 (30.5%) healthy controls. Fifty-three (55.7%) were male, mean age 54.4 (SD 10.2) years. COVID-19 patients presented significantly lower VD than healthy controls: central (p = 0.003), inner ring (p = 0.026), outer ring (p = 0.001). PD was also significantly decreased: outer ring (p = 0.003), full area (p = 0.001). No differences in OCTA parameters were found between COVID-19 patients with and without TE. CONCLUSIONS: OCTA represents a promising tool for the in vivo assessment of microvascular changes in COVID-19. Patients with SARS-CoV-2 infection show lower VD and PD compared to healthy controls. However, no differences were found between COVID-19 when considering TE. Prospective studies are required to further evaluate the retinal microvascular involvement of SARS-CoV-2 and its impact on the vasculature of other organs.